Gas lift is a technique where fluid is injected in the tubing string from the surrounding annulus to reduce the density of the produced fluids and in turn allow the formation pressure to lift the less dense mixture to the surface. To accomplish this a series of valves that allow access from the annulus into the production tubing are used. These valves are inserted in side pocket mandrels so that a clear production string is available for running in or removing tools using the production string. The predetermined position of the gas lift valves controls the entry points for gas into the production string.
As the well produces the operating conditions can change and call for gas lift at a new location that is generally deeper or further from the surface than the location of the existing gas lift valves. The new location needed for gas lift can also be below an existing isolation packer. What is needed and provided is a retrofit way of getting access and an injection location at a new desired location without pulling the production string to reconfigure the location of the annulus access locations. This can be done by either employing exiting wall ports in the tubing string regardless of their location such as sliding sleeves. The insert is installed and latched to straddle the tubing string wall port so that annulus pressure can be directed through the insert into tubing supported from the insert so the precise desired location for the admission of the injection gas can be obtained. The produced fluids come to the surface around the injection tubing and bypass the inlet piping from the annulus into the injection tubing. Alternatively, a port can be produced at a desired location in the production string and an insert straddle tool can be located on an anchor to straddle the new opening. The insert can have tubing so that the injection point can be predetermined. The insert can be removed and in the case of a sliding sleeve valve as the access location, the sliding sleeve can then be closed. Those and other aspects of the present invention can be more readily appreciated from a review of the description of the preferred embodiment and the associated drawings while appreciating that the full scope of the invention is to be determined from the appended claims.
The following references discuss gas lift systems and show side pocket mandrels that are used to house valves for access from the annulus at predetermined locations into the production tubing: U.S. Pat. Nos. 7,360,602; 7,228,897 (shows cementing through side pocket mandrels); U.S. Pat. Nos. 6,810,955; 5,862,865 (shows insert safety valves for a retrofit for gas lift using existing control lines) and U.S. Pat. No. 5,896,924 (shows computer control of gas lift valves).